This invention is related generally to shoes and, more particularly, to pneumatic cushioning therein.
Prior art shoes have involved a variety of inflation devices disposed at different locations. For instance, previous shoe arrangements have included soles that can be inflated at the arch to provide support. Other shoes contain soles which have sealed inflated chambers disposed within the soles in order to increase vertical bounce. These previous chambers are soft-sided bladders which distort into a more convex or spherical shape upon inflation. If the walls of the bladder are not constrained, for instance, by the structure of the sole of the shoe, the distortion occurs in every direction.
Others have addressed this problem by placing a foam core inside the bladder and adhering the entire surface of the interior bladder walls to the entire exterior surface of the foam core as is taught in U.S. Pat. No. 5,235,715 to Donzis. This arrangement of adhering all of the surface of the foam core limits the shape of the bladder to the shape of the foam core and does not allow for differential distortions of the bladder as the bladder is inflated. Such prior art shoes also have not allowed for selective adjustment of the pressure in the bladder chambers and may result in uneven air distribution in the sole of the shoe.
Pumps in prior art shoes have typically been either externally connectable to the shoe""s air chambers or positioned in low stress areas on the upper portion of the shoe such as in the tongue or on the back of the heel. Such prior art shoes encounter different problems in use. For externally connectable pumps, the pump must be retrieved whenever inflation is desired. Pumps positioned on the upper portion add bulk to the shoe and limit agility. Such pumps also inhibit aesthetic choices in shoe design. Aesthetics may be particularly vital for golf shoes or non-athletic shoes.
In addition, the typical prior art shoe arrangements have either utilized pump actuators which were nonintegral with the shoe and required connection before inflation and disconnection before normal shoe use, or pump actuators which were connected to the external surface of the shoe, such as on the heel as in U.S. Pat. No. 5,222,312 to Doyle. Nonintegral pump actuators require that the shoe wearer retrieve the actuator every time inflation is needed. External pump actuators impose aesthetic limitations on footwear and add bulk to the xe2x80x9cfootprintxe2x80x9d of the footwear.
Prior art shoes which have incorporated adjustable pneumatic cushioning have typically provided several air chambers in different areas of the sole which are interconnected via tubing. Eliminating the use of several distinct chambers would further reduce the weight of the shoe and simplify shoe construction. In addition, a complementary configuration between the pump, pump actuator and the air chamber or bladder could significantly reduce the bulk of the shoe.
It is, therefore, desirable to provide for improved pneumatic cushioning in footwear while including all necessary components for such cushioning within shoe and minimizing shoe bulk and aesthetic limitations. A shoe sole which addresses the problems of known footwear would be an important advance in the art.
It is an object of the invention to provide an improved pneumatic cushioning system entirely within the confines of a shoe sole.
Another object of the invention is to provide a pneumatic inflation device which is fully recessed in a shoe sole.
Another object of the invention is to provide a pneumatic inflation device with a locking mechanism to secure the pump actuator entirely within the sole and flush with the sole""s outer wall when not in use.
Another object of the invention is to provide a locking mechanism which is easily finger-operated to facilitate inflation by a shoe wearer.
Another object of the invention is to provide a recess for storing the pump actuator to prevent damage thereto.
Another object of the invention is to provide a pneumatic inflation device in which the bladder and pump are complementary configured so as to minimize shoe bulk.
Still another object of the invention is to provide a pneumatic inflation device entirely within a shoe sole, in which the pump is positioned to avoid excessive stress.
Still another object of the invention is to provide a pneumatic inflation device entirely within a shoe sole, which includes a pressure-release valve to permit adjustment of bladder pressure.
These and other objects of the invention will be apparent from the following descriptions and from the drawings.
This invention is an improved device for providing pneumatic cushioning within a shoe sole. The invention represents a significant advance over the state of the art by providing a shoe sole which encompasses every necessary component for adjustable pneumatic cushioning.
The device includes a pump which is entirely within the sole, a pump actuator which is entirely within the sole when not in use, and an inflatable bladder which is entirely within the sole and is operatively connected to the pump.
The inventive device can further include a locking mechanism which secures the pump actuator within the sole. It is preferred that the pump actuator can be locked only when the pump-actuator cap is flush with the outer wall of the sole. Such an arrangement facilitates use of the locking mechanism by the shoe wearer. The locking mechanism is finger-operated to further facilitate use by the shoe wearer.
The pump actuator preferably includes a piston rod having a distal end which is attached to the pump-actuator cap. The cap is rotatably movable between locked and unlocked positions only when the cap is flush with the sole. The cap is movable in this position due to the structure of the piston rod. The piston rod includes at least one radially extending portion which also extends axially from the piston towards the cap. However, the radially extending portion does not reach the cap, rather, there exists a gap adjacent the cap.
The pump-cylinder top includes a slot which is sized to accept the piston rod and the radially extending portion. The piston rod can be moved in and out of the pump-cylinder freely. However, if the piston rod is inserted so that the radially extending portion moves completely past the pump-cylinder top, the rod can be rotated so that the radially extending portion is not positioned in-line with the slot. Thus, the pump actuator is locked in position within the pump cylinder.
The device is preferably positioned such that the pump is between the forefoot-pressure portion and the heel-pressure portion which strikes the ground first during walking or running by a typical shoe-wearer. This positioning prevents the pump from being damaged during the lifetime of the shoe.
The device is also preferably positioned such that the pump is oriented transverse to the longitudinal axis which passes from the heel to the toes. The device is more preferably oriented substantially perpendicular to that longitudinal axis.
The device is further preferably positioned in the midsole of the sole. The midsole being located between the outer sole which contacts external surfaces and the in sole which can typically be removed by the shoe-wearer.
The preferred bladder includes a bladder membrane which has an interior and exterior side, a foam core contained within the bladder and having a plurality of sides, and adhesive disposed on only one side of the foam core, and a portion of the interior side of the bladder membrane adhering to the adhesive.
The inflation device preferably further comprises an inlet conduit within the sole and connecting the pump to the bladder, a unidirectional flow valve between the inlet conduit and the bladder, a pressure-release valve within the sole and operatively connected to the bladder to permit the release of air from the bladder, and an exit conduit connecting the pressure-release valve to the bladder.
In order to minimize the bulk of the shoe, it is most preferred that the pump be positioned at least partially within the bladder. More preferably, the pump is positioned entirely within the bladder. In such a preferred embodiment, first and second inlet conduits have distal ends connected to the first and second bladders and proximal ends connected to a flow switching device, first and second unidirectional flow valves are disposed, respectively, within the first and second conduits and between the flow switching device and the first and second bladders, respectively, and first and second pressure release valves are operatively connected, respectively, to the first and second bladders.
The preferred device may also include a third bladder connected to the flow switching device by a third conduit; a third unidirectional flow valve between the flow switching device and the third bladder; and a third pressure release valve connected to the third bladder.
The invention also includes a pneumatically cushioned shoe having a sole and comprising a pump which is entirely within the sole, a pump actuator which is entirely within the sole when not in use, and an inflatable bladder which is entirely within the sole and is operatively connected to the pump. The pump actuator preferably includes a locking mechanism securing the pump actuator within the sole. The pump actuator more preferably includes a piston rod having a distal end with the locking mechanism including a finger-operated cap which is attached to the distal end. The cap is movable between locked and unlocked positions only when the cap is flush with the sole as discussed above.